Ford has repeatedly denied the allegations and the video has failed to surface. Reuters cannot confirm the existence of the video or its content.

Despite the episode, the mayor has continued to enjoy a hard core of support from a segment of Toronto voters, particularly in the suburbs, who lifted him to power in 2010 on a platform of controlling spending and cutting taxes. Ford says he plans to run for reelection.

Ford is the third Canadian politician to admit to using marijuana in less than a week. Ontario premier Kathleen Wynne said earlier on Wednesday that she had smoked the drug "very infrequently" decades ago, but stopped before getting into politics.

Wynne was answering a question about federal Liberal Party leader Justin Trudeau, who said in an interview published last week that he last smoked marijuana about three years ago, after being elected to Parliament, and had used the drug five or six times in his life.

Marijuana use remains illegal in Canada, with the exception of medical marijuana, which is used to manage chronic pain and for conditions that include multiple sclerosis and arthritis.

There have been numerous pushes to decriminalize its use, with supporters arguing it should not be grouped in with more addictive and powerful drugs. Critics argue that marijuana can be a "gateway drug" to abuse of other illegal substances.